It is a common practice to fix a vertical gnomon and study the moving shadowcast by it. This shows our local solar time and gives us a hint regarding theseason in which we perform the observation. The moving shadow can also tell usour latitude with high precision. In this paper we propose to exchange theroles and while keeping the shadows fixed on the ground we will move thegnomon. This lets us understand in a simple way the relevance of the tropicallines of latitude and the behavior of shadows in different locations. We thenput these ideas into practice using sticks and threads during a solstice on twosites located on opposite sides of the Tropic of Capricorn.
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